We need to use 'now', not 'current_timestamp', which the time parser no longer recognizes.
Note that current_timestamp, the variable not the quoted string, does of course work.
I ran into this myself yesterday and have fixed it on head.
The problem has to do with the way define_function_args is written - it quotes the default values (or passes them as :tclvars to the driver, which does the quoting, not sure which). In retrospect it would be best if define_function_args didn't do that but it's not worth changing at this point.
I guess this needs fixing for 5.0.1 too? Changing "creation_date;current_timestamp" to "creation_date;now", that is, in calls to define_function_args.
Sigh ... all these near-silent changes the PG group makes bite us in the ass, don't they? :)
